The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Referring now to FIG. 1, a functional block diagram of a vehicle powertrain 100 is presented. The powertrain 100 includes an engine 104 and a transmission 108. Air is drawn through a throttle valve 112 into an intake manifold 114. An air-fuel mixture is created by injecting fuel from fuel injector 116 into the intake manifold 114. The air-fuel mixture is drawn through an open intake valve 118 into a representative cylinder 120. Alternatively, the fuel injector 116 may inject fuel directly into the cylinder 120.
An ignition coil 122 activates a spark plug 124 to ignite the air-fuel mixture within the cylinder 120. After ignition, an open exhaust valve 126 allows the cylinder 120 to vent the products of combustion to an exhaust system 128. An engine control module (ECM) 130 receives signals from sensors, such as an engine coolant temperature (ECT) sensor 132. The ECM 130 then controls various actuators of the engine 104, such as the fuel injector 116 and the ignition coil 122.
Torque from the engine 104 is output to the transmission 108 via a transmission input shaft 138. The transmission 108 outputs the torque to a driveline (not shown) via a transmission output shaft 138. The ratio between the speeds of the transmission input and output shafts 136 and 138 is controlled by a planetary gearset 140.
In various implementations, the planetary gearset 140 may be a complex planetary gearset, such as one including one ring gear, two sun gears, and two sets of planet gears. Alternatively, the planetary gearset 140 may include two or more complete sets of planetary gears, various components of which can be connected to each other and to the input and output of the planetary gearset 140.
The ratio between the input and output shafts 136 and 138 is determined by which of the components of the planetary gearset 140 are held stationary and/or connected to each other. Components of the planetary gearset 140 are controlled by a plurality of friction devices, including a first friction device 142 and a second friction device 144.
The first and second devices 142 and 144 are controlled by first and second actuators 146 and 148, respectively. The first and second actuators 146 and 148 are controlled by a transmission control module 180. The transmission control module 160 receives signals from various sensors, including a transmission fluid temperature sensor 162 and a transmission ratio sensor 164. The transmission ratio sensor 164 may determine the ratio by dividing the speed of the transmission input shaft 136 by the speed of the transmission output shaft 138. The transmission ratio sensor 164 may be located in the transmission 108 and may determine the speeds of the input and transmission output shafts 136 and 138 based on engine speed and wheel speed, respectively.
The transmission control module 160 receives data from the ECM 130. The transmission control module 160 may receive signals from a transfer case control module 166, such as may be implemented in a four-wheel-drive or all-wheel-drive vehicle. The transmission control module 160 receives signals from a shift selector 168, which is operated by a driver of the vehicle. For example only, the shift selector 168 may be a column-mounted or floor-mounted PRNDL lever. The transmission control module 160 receives calibration parameters from nonvolatile memory 170 and may store state information in nonvolatile memory 170.